multi site sub directory urls

hello.

I have a main site with a few other sites with almost no traffic.

I want to install all my sites in your hosting plan.

i use a multisite with sub directories.

i am wondering how the urls will stay the same ..???

for example. one site (main) is iq-design.eu

the other will be iq-design.eu/test-1.

Now on that site i will put a domain Holistic-Life.com (for example)

How my urls will be the same like before i move the site???

holistic-life.com/index (for example)

Mapping a new domain as from your help i learn it is easy after WP 4.5

I will start with one site to see how it is working and if their is no problem with urls i will move all my sites on your hosting plan.

Thanks a lot.