Help needed rebuilding part fallen down garden wall

[Newandlackingability]

I have a part built garden wall in an area in my garden. Not vital, but have the bricks/blocks that time has knocked off. I want to rebuild myself, because if I muck it up it does not matter. I want to do a best job I can. On B&Q website you can buy the ready made mortar, but there are so many I do not know which one to buy? Can anyone help? What ready made mortar packs should I buy? What tools? Thanks

[welsh brickie]

go to your local builders merchants and buy bags of sand, cement and plasticiser, its cheaper.
You will need a spirit level , trowel, hammer and bolster, go on youtube for more tips