Downshifting to 2nd or 1st while moving (technique)

theboydiddy

there is a pretty interesting question.... what gear should i be in going between 30-60mph and 70-90mph?
my car is brand spanking new, so i was told to take it easy on her and break her in. to NOT speed nor push the gear to its max until i reach 2k miles. i only reached 450 miles today. also it is my first manual transmission car and i haven't driven M/T in about 9 years... i feel a little lost at times. i stall it from time to time, my clutch is too high up (i think)
idk I'm just a tad bit confused.