You’ve seen https://digitransit.fi and some instances like https://digitransit.im.verschwoerhaus.de https://herrenberg.stadtnavi.de https://digitransit.codeformuenster.org https://cityrouting.e-gpp.hr https://next-dev.oulunliikenne.fi. Now you’re interested in how to get a digitransit for your own region. This could be a helpful step-by-step guide for you :)
If you attempt building your own deployment for the first time, budget for a few hours. With a bit of experience, deployment times of about half an hour are realistic.