If want to check which .net core version, sdk’s and runtimes are installed on your machine you can easily check in console by typing:
dotnet --infoYou will get a result looking like:
Like mentioned in the result you can install another version or sdk by visiting https://aka.ms/dotnet-download and following the instructions or do it directly in visual studio.
There you have to open the project properties and select the targetframework dropdown. You can find an option named install another framework there. By clicking on it the browser opens and you’ll be transfered to https://dotnet.microsoft.com/download/visual-studio-sdks where you can download runtimes and sdk’s.