Beginner Task: Change header "call us" into link / delete "Sign in"

[Bob_K]

Hello everybody,

I've been searching in circles for hours now. I want to edit the header.

1. "Call us 0123 4567" should be deleted and exchanged for a link that leads to the contact page/contact form.

2. The "Sign in" button should disappear on the main page.

Searching the forum didn't help me. I'm a beginner in PrestaShop, probably missing the right search terms.

PS 1.7.8.7 and the Classic template.

Thanks.