As your first game, there are four recommended choices.
Strategy (and most translated), dating sim, trainer, and RPG respectively.
For a more complete guide, go here Computer-assisted translation.
Era Games History
As a whole, the era games are text-based SLGs (simulation games) built around the eramaker engine. The term covers dozens of different games; most of them are built around the idea of raising and sexually training one or several girls and seem to have the most intricate sexual interfaces ever seen before in an H-game.
To understand where the differences and similarities come from, let us sit down a bit for a history lesson. In August 2003, a group known as Circle Baku released its first game called [era], a doujin game with characters from the eroge Kizuato, where the player gives sexual training to a kidnapped Kaede. It was the precursor to the era games, but it was the release of erakanon in 2005 that sparked the Japanese era games development scene.
Released as a free game by Circle Baku in December 2005, erakanon is a text-based game expanding on the sexual training framework of the original [era] with characters from the Kanon franchise. But most importantly, Circle Baku also freely allowed the modding and redistribution of its base engine, called eramaker. Since then, Circle Baku has released several games on its era series (although not using the eramaker engine itself, keeping to a more visual-oriented style) while the era community has maintained and created several text-based games with the eramaker engine. The Japanese community has also created an emulator for the eramaker engine called Emuera, which corrects some bugs and adds new scripting features allowing for advanced gameplay customization.
As the original eramaker engine only allowed for the modification of its CSV data files, the first fanmade games were basically versions of erakanon with different characters from different franchises. After the release of Emuera, though, the era games became quite diverse, with several different gameplay styles, including RPGs, strategy, management, raising and training simulators. The western era games community started up in May 2016, with a thread started by the user Coold in the ULMF forums. He did a partial translation of the eraTohoK game – a strategy game with characters from the Touhou franchise. At the beginning of August that translation was posted on 8ch’s /hgg/ boards, and quickly sparked interest not only in eraTohoK itself, but in era games as a whole. Several anonymous users picked up the translation of eraTohoK and some other games, in a loosely organized but surprisingly efficient way.
This section covers some more general info about era games. The information is not accurate for all games, but as they all share the same base they do have similarities. For instance, pretty much all trainer games have the same progression system. Feel free to skip this, but it might give some insight into why things are the way they are.
The games are divided into two sections, TRAIN and BASE. BASE is where the player can save and load, change settings etc. It's often here they go after loading. In trainers the player can buy/sell and items etc. In strategy games like TohoK most of the game takes place in BASE.
TRAIN is where the player can actually do things, often being given a bunch of commands. There are often bars and info present to display the status of what's going on. In tohoTW every waking moment is spent in TRAIN. The important difference is that the player cannot save and load in TRAIN mode.
This leads to SOURCE, which is generated by commands in TRAIN. The most common ones across games are C Pleasure, V Pleasure etc. After an action is done, all the SOURCE is summed up and converted to PALAM, probably an engrish way of saying "param(eter)". The bars present in most games depict PALAM, often with game-specific levels. The amount of PALAM at the end of TRAIN creates GEMS, well technically they are called "JUEL", as in jewel, but never mind that. Gems is also translated different in some games, being at times called spheres or similar.
Gems are kept between sessions, and are used to increase ABL, for instance Intimacy, or Obedience. In trainer games these are easy to see as the player is often on a deadline. But in games like TW and TohoK they are not visible. ABL sometimes need experience to increase as well, these are often generated per-command, so using handjob once gives one handjob exp.