a. What is the best tire pressure front and rear?
15 PSI all around is good, if you really stuck then defalte to 12 PSI for self recovery. If you continue drive at 12 psi, then make sure dont take high speed turn or else tire will pop out.
b. Which Transfer shift lever position I need to use, 4H, 4HLc or 4LLc?
Plain beach sand: 4H, decent desert drive: 4HLc is good, if you stuck or need to tow someone: 4LLc
c. Which gear is best 2nd or 1st gear or all-time D?
D is all time good for drive, if stuck or in deep sand you can drive at 2nd gear or even in 1st gear. If you drive manual then make sure you keep switching gears often to not to strain any one specif gear.
d. Which range of acceleration is best?
High range is advisable, Lo range only for self recovery, towing, or making impossible climbs.