Metamask supports the Astar network and allows users to transfer tokens and sign transactions. More details are in Astar's documentation.
When you connect Metamask to Algem dApp, Algem will automatically change the Metamask configuration to Astar Network. Still, if you need to add the network manually, you can find the configuration below.
More information in the Astar Network documentation:
To add a token on Metamask, such as nASTR, you can use the feature on Algem dApp or add it manually using the contract address below.