Use search engines like Google, Bing, etc., and type in the details you have. You might want to include terms like "game guide," "walkthrough," or "RJ01213396 guide" to find specific information.
: Risou no Otousan Tomodachi (理想のお父さん友達) Circle : Chocolatier risou no otousan tomodachi dlc rj01213396
: While the base experience is often found on platforms like DLSite (where the RJ-code originates), mobile versions (APK) also exist for Android users. Use search engines like Google, Bing, etc