how do I re-adjust my gears? thanks.

Hi, How do I adjust my slipping gears? got a new bike, went out about 3 times, good fun, but on the trail ,the top low gear (climbing) just went over-board and got stuck several times between the biggest sprocket and the back wheel spokes. also the chain will now stop at the last but one small spocket when I try to shift to high (fast) gear. It looks like the whole gears system has moved one nudge up….what bits shall I twick please, thanks. Please use plain English,as you can gather I ain’t no mechanic, thanks!

Park Tools website is your friend

Forgot to mention – if the bike is 100% new your problem could also be related to the cables stretching as they ‘bed in’, this is pretty normal.
You should find little adjusters on your shifter and rear mech -in both cases these will be where the cable enters the body of the component. Give either of those a 1/4 turn at a time and then test the gears again, if you sense that changes are getting beer then it may just be a case of using these adjusters. If not then refer to the Park site for how to adjust your rear mech. If you really are as mechanically challenged as I used to be suggest getting a knowledgeable friend to show you how or take the bike back to the shop and ask them to make the adjustment, showing you how to do it as they go… no need to be embarrassed bout taking it in – they’ll be used to having to fine tune new builds.
Hope that helps
Chris

Will the bike shop where you bought the bike not do a tune up for you?