Any time you search in multiple databases, you will get duplicate results. Keeping track of your numbers before and after deduplication is something you will want to note in your PRISMA diagram. There are many different tools that can help you with this step, but they all have their pros and cons.
Once results have been deduplicated, you will begin the screening process. This is where you begin to apply your inclusion/exclusion criteria. While systematic review methodology requires all inclusion/exclusion criteria to be defined a priori, scoping review methodology allows for ad hoc inclusion/exclusion criteria based on the researchers' increased familiarity with the research at this point. Just be sure to document!
There are many free and paid tools available for this stage as well.
Start with a title and abstract screening to exclude those studies that are obviously outside of your parameters
The final stage will be full text screening. This is best performed by three screeners, screening independently from one another.
*Recommended tool - Rayyan - free, browser-based screening software