I'm so excited to hear that you're interested in using QuickBooks Desktop Pro to manage your books! Making the decision to switch the software you're using for your business's bookkeeping can be a big undertaking, and I love that you're considering QuickBooks. I can explain the options for making the switch so that you can get down to business.
While there isn't a direct method or tool recommended by Intuit to make this switch, it is possible to import certain data into QuickBooks Desktop. I'd like to start you off with the following article: Import and export data in QuickBooks Desktop. This is a useful help article because it outlines and links you to other resources to learn what information can be imported into the program and what file types you need to do so. Since there are some specific file types to import data, I recommend double checking the options for exporting your information from Sage 300 ERP and considering a file converter service if needed.
There may also be third-party services out there that can convert your Sage data to QuickBooks Desktop for you. I don't have any that I can recommend, but you can do some research to see if there's something that meets your needs and budget to make the switch. You may receive recommendations here from other users, but feel free to do your research to make sure they're right for you.
If you have any questions during the setup process of your QuickBooks Desktop company file, don't hesitate to connect with our team to get some guidance. The Intuit QuickBooks Desktop software support policies page outlines support options, hours, and other important details to keep in mind when you reach out.