l need to know where to put the sleeping bag in the rucksack

You do not put the sleeping bag in your pack. If you are using a duffle bag, just carry it seperate. If you have a back pack, secure the bag to the bottom or top (depending on where the mounts are) of the pack.

If u plan to backpack, the rule of thumb for packing is to put lighter items at the bottom of the pack & heavier items at the top. That seems backwards, l know, but it is easier to support the heaviest items up near ur shoulders as long as ur pack fits well & u secure both the waist & chest straps. If it is not serious backpacking/hiking/camping, then carry the sleeping bag separately since it is likely to be the bulkiest item u bring. If u camp on a regular basis, u will want a pad to put under ur sleeping bag to shield u from the hard ground. You can find several options at any sporting goods store. Have fun!

If securing the sleeping bag to the top of your backpack, be sure to secure it so that it does not swing about and throw you off balance. If attached at the bottom secure it well so it does not swing about. A friend of mine had it bumping his butt with every step of a twenty mile hike. He couldn,t sit down for the rest of the trip due to the blisters on his butt.