WordPress on Mac with Mamp

After changing from being a PC user to Mac, I’m having trouble installing WP on my Mac. Any advice appreciated:

1. Because I’m building a site as Local first, I’m using MAMP. Before I was able to use it, I had to change ports because the default 8888 is “in use.”

2. After MAMP is running, wp-admin/install.php keeps opening as text in my Text app

3. When I try to open it in either my Firefox or Safari browser–they are greyed out in the App choices, and I have to change setting from “Recommended Apps” to “All Apps” to be able to choose Safari or Firefox.

4. BUT when I chose a browser and try to open wp-admin/install.php — numerous blank browser windows start opening. The only way to stop the flood is to shut down MAMP.

I used to be expert at setting up WordPress & WAMP on my PC–but I’m a different world not.