Posted: Yesterday at 17:17
From reading your description of what you did you made a basic mistake. You compacted the soil by rolling it. You don't roll a lawn till its established. You have probably compacted too much and seed will struggle to put down roots on compacted ground. You only need to tread a seed bed and after treading you rake the surface to a fine tilth then seed and water daily.
Roundup pathclear will prevent seed germination, roundup glysophate weed killer will break down on contact with the soil.
Firstly which roundup did you use?
If it was the weed killer then break up the surface of the soil again, then tread, re rake then resow. You don't want compost on it, just get the basics right and be patient. The weather at the moment is ideal for sowing a lawn, 10 - 20 days for germination, you won't get a decent lawn for several months, so don't expect too much too soon.