How to lay flagstone?

This article has some awesome tips. Good luck to you!

http://www.thespruce.com/how-to-lay-a-flagstone-patio-2132237

I am not a big weed block material fan. Weeds will grow on top of weed block once dirt or soils blow in on top. Then you have to dig it all up and start again. You are better off pulling the weeds and then be faithful with the weed preventer . I like preen.

I agree with Shoshana, the soil will eventually build up enough that weeds will grow above the weed block. You may have to level the ground under the flagstones, Even if you put down sand if the area under it is uneven it will eventually run out from the lower areas under the stones and they will be as uneven as the ground is. The preen will definitely help with the weeds, although any that grow off the roots of another plant and tree seeds will not be prevented from germinating. Hope this helps.

For level blocks, you may need a layer of small gravel and then a layer of sand. To prevent weeds, put a layer of cardboard down first and then layer your other materials. Also, periodically sprinkle pure salt or baking soda between the pavers to prevent weed growth. Be aware that nothing will be able to grow there if you do that, so be careful.

The uneven stones may be because the crushed rock base was either not deep enough or well packed, adding sand will only be temporary. The weeds can be taken care of by: boiling water, salt or vinegar....being careful not,to damage plants outside the paving.