My dentist recommends me to have surgery and have implant. How long does it usually take for the entire process? I know it depends, but average

Depends on location. If you're replacing a front tooth, very often there isn't enough bone thickness for an implant so a bone graft has to be done first, sometimes for back teeth too. If a graft isn't required, it can take 4-6 months for bone to grow around the implant so that it is ready to restore with a crown. If a graft is required also, the process can take about 8-10 months.