Click on My eBay, top right of page, and near the top on the righthand side of the next page there should be some text saying Make ..... your My eBay home page. You may need to opt out of seller hub first. If so on the seller hub selling/listing page, in the box titled Selling Tools the bottom option is Opt Out. You can opt back in afterwards if you prefer it.
If you have any problems with that you can also do it via your browser. Click on Edit, top of your screen > Preferences > Home > Home Page > insert required URL.
