I already figured out. how to steal cars, I put 3-4 members on hijacking but nothing happens?
To steal cars you need to go to the gang menu, select the member and in their menu purchase car jacking equipment for them. Then they should be stealing a car per member during night as long as you have them assigned to the hijacking job.
A short summary of what i've figured out about the gang mechanics, in case they are useful as a guide to anyone else:
To start the gang you need to befriend any male character and then ask them to join your gang. Many people will say no even if they like you, probably some mechanic about their values or priorities. Junkies is my go-to way to recruit (being a junkie has no downside in the gang from what i have seen), they don't mind that kind of stuff.
You can find males to befriend either in the theatre (sometimes men, sometimes women) or by watching a show in the strip club. Starting in university is also useful as you have a lot of male classmates that can be used for something more than just selling drugs to.
You need three people to make money off your gang, this is done by doing robberies.
Your gang members can also be assigned to guard your prostitutes which saves you some money.
You can also assign a gang whore for their "free use", the usefulness of this is unknown but can cause her to be hurt which doesn't help you in any way.
If you want to commit a robbery you need to have scouted a job, have one stolen car, assign one driver, one gun man (has to have a gun of some sort equipped) and one bag man (no special equipment needed). Guns can be bought from the bikers in the slum.
Scouting is done bit by bit by your assigned scouts in the gang. They have to be specifically assigned to scout a robbery and then work on that for a while. If you use multiple member, they are skilled and have surveillance equipment they can scout a new robbery in a day, otherwise it usually takes a couple of days.
After the robbery is scouted you can assign people to the roles mentioned above, then they will run the heist when you end the day. Can go either good, "just not bad" or bad. Save beforehand if you don't wanna have to start your gang all over again...
Sometimes you have it all done correctly but the robbery doesn't happen when you end the day, if this happens try unassigning these three robbery-specific jobs from your gang members and then re-assign them one by one, this has worked for me when it happened.
There is also some kind of gang mechanic where you can assign a leader of your gang, and then interact with other gangs. One gang buys stolen cars, another can give you jobs to scout for people who owe them money which you then go to collect. Then there are dozens more that have no use or purpose at all from what i can tell.
The collection job/mission game mechanics is not good, usually they can't pay you the full debt and the gang that gave you the job still expects full payment from you. Only upside is you can pressure the person into being a prostitute if they can't pay, but from what i understand they will stop being a prostitute when their debt to you is paid so what is then the gain at all of doing all that?
That's the stuff i remember to talk about right now off the top of my head, but i probably have more stuff i don't think about right now. I've never looked at the code, so all my knowledge is only based on what i've figured out from playing on and off for the last two years or so.
If you have any specific questions you can try to ask in a reply to my post and and i'll try to remember to reply when i check by the site.