The soil you use is extremely important for the result you will achieve, so do not save on this and buy some decent loam at your local garden store. Another important aspect concerns the pots in which you are going to grow the plants. They should not be too small because this might otherwise obstruct the growth of the plant. It is also wise to have pots with holes in the bottom, so that the surplus water can be drained.
When you have filled the pots with soil and you have germinated the seeds, then you can put them in pots. Place the weed seeds approximately 1 cm underneath the ground. Depending on the type it will take 1 to 10 days before the result can be seen. As of the placing of the seeds, take care of the right temperature, enough light and keep it humid enough.