How to point a TK domain to a heroku app?

Question

I'm a noob. I've set up a tk domain here http://dot.tk/ I'd like to point to myapp.herokuapp.com. How can I do it?

I cannot figure out what entry to add, ARecod, Cname, MX record? What do I put in the HOST and IP fields? I keep getting "invalid data". Should I choose TK domain service or custom domain service?

In heroku I typed

heroku domains:add myapp.tk

Now what do I do? Please, I'm not looking for an explanation as to how domain forwarding works. I'm sure as a network expert, you can spend hours studying it. I just need to know how to give my app a tk domain. Thanks

These are the panels I see

UPDATE

I've managed to do it with a CNAME record HOST=www.myapp.tk and IP=www.myapp.herokuapp.com but after 30 minutes they both stopped working and give a 404 error!? Is heroku blocking .tk domains?

UPDATE2:

I've registered another tok domain name. The www.myapp2.tk works but myapp2.tk does not work. My older www.myapp.tk and myapp.tk still give 404 error. Does anybody know how to fix this? I've done the following heroku commands:

heroku domains:add myapp.tk
heroku domains:add www.myapp.tk
heroku domains:add myapp2.tk
heroku domains:add www.myapp2.tk

Answer 1

1. In "cname record": host: www.myapp.tk ip-addres: herokuapp.com .

2. ping - a herokuapp.com in cmd and get ip, e.g. herokuapp.com [174.129.22.189]

3. add a-record host: myapp.tk ip-addres: 174.129.22.189 .