To change the style of this button, I suggest you to click on Customize. Then, you’ll see blue pencils on your homepage. Click on the one related to the Hero, like shown in the attached screenshot.
Then, click on the Style to edit the style of the section. You’ll be able to change the colors used for the button, like shown in the attached screenshot.
To change this text we really suggest to use the Loco Translate plugin, as describe in the link I send you in my previous answer:
If you need help to install a plugin, click here.
Once installed, go to Dashboard > Loco translate > Plugins > Grimlock for BuddyPress. The first time, perhaps you’ll have to create a new language. In your case, select the language of your website. Then, search the words you want to change.
If you don’t find this string, I suggest you click on “Synchronize”. It will automatically add the new strings.
Let me know if you need more explanations. 🙂