As the first step, we highly suggest checking out an article Migrating to Shopify from another platform, to guide you through the steps of the process and further introduce you to Shopify.
The next step in the process would be choosing a theme for your store. There are so many themes on the market and this could be probably the most difficult step. Therefore, we highly recommend purchasing a premium theme, such as the ones built by CleanThemes, Pixel Union, Underground, or Out of The Sandbox, for your new store!
This is perhaps the most important aspect about starting your store, because it will save you money spent on fixes you won't need to make later. Aforementioned themes are pixel-perfect and responsive across all devices. The price is higher than run-of-the-mill themes, but in our opinion, it's well worth it.
When choosing your theme, pay close attention to the functionality of the product page and collection pages, to be sure it's the closest possible match to the type of product you're selling. It will also save you money because this is where most store owners end up spending a lot of cash, after purchasing the theme, which makes this the second most important aspect — your website is an online store above anything else.
Additionally, should you need further assistance with a migration we can suggest reaching out to Brave The Skies company, as they can help you with the migration process.
Once you've registered your new store, and you've purchased and installed your theme, you may need small fixes, to fine tune it to your taste. This is where we can help you, as we focus on small jobs, up to 1 hour long. Check out our Small Task Catalog here.