Preflight Planning, I set the STAR of the airport and already have the missed approach and hold at certain INT and altitude. It is rather easy. However, What should I do for the FMC to exit the hold pattern, regain the G/S, LOC of the runway and get back the autolanding

If I understand your question, you are holding after a missed approach and you want to shoot another approach. It's up to ATC (real world) how you are going to get routed to the next try, and it depends on the orientation of the holding pattern to the IAF. There is no one best way.However, if you just want to play with the FMC why not exit the holding pattern with HDG and fly a standard approach to intercept the final? Use the LSB to "promote" the IF or FAF to your next LNAV waypoint when you have set up an intercept course.If you need help programming the FMC you need to be more specific.

The easiest way is just to enter another approach on the arrivals and departure page. Line select the first waypoint you want to use on the approach up to the top. Enter the inbound course in the interecept course to boxes (bottom right) and then execute. All you need to do now is use heading select to steer yourself around to be able to do an intercept onto this extended approach centreline. If the aircraft starts to do silly things like random orbits or not follow a chosen heading or track (following the Missed approach)then disengage the AP and re-engage it.CheersSteve