On 2, to do it properly you'd need to remove the grass first, as it stops other plants growing by taking all the moisture and nutrients out of the soil. There's loads of online resources to describe how to do it.
I believe that sowing yellow rattle seed is an easier way to start as it inhibits grass growth, but you need to do it in autumn and give it a head start by raking the lawn and exposing some bare soil.
The really easy way to do it, and now is the right time to start, is to stop mowing the lawn through the spring and just let it grow, then mow in the late summer or autumn. However there might not be other plants in your lawn that can benefit from this.
On 2, to do it properly you'd need to remove the grass first, as it stops other plants growing by taking all the moisture and nutrients out of the soil. There's loads of online resources to describe how to do it.
I believe that sowing yellow rattle seed is an easier way to start as it inhibits grass growth, but you need to do it in autumn and give it a head start by raking the lawn and exposing some bare soil.
The really easy way to do it, and now is the right time to start, is to stop mowing the lawn through the spring and just let it grow, then mow in the late summer or autumn. However there might not be other plants in your lawn that can benefit from this.