how do you replace the bags ?

Make and model needed as there are many bags that are fitted differently.

Former Bag man and vac repairer retired. Some do need a memory jog but I think sarcasm can be dispensed with Good luck...
You could also try a search on youtube someone may come up with your machine or go to the company website you may be able to download user instructions.

bob
April 2015

Danny - much will depend on the make and model of your cleaner - you do not say.

The general case is that it's relatively obvious - open the machine - take out the old bag - noting how it fits in - and put in the new bag the same way - child's play almost. You might ask a local child.

Good luck...
April 2015