The microSD car will have come with an adapter, as this one does for example:
https://images-na.ssl-images-amazon.com/images/I/614r08dDNhL._AC_SL1406_.jpg
Dig it out from wherever you put it and put the microSD card into it.(effectively giving you a regular SD card).
Insert the composite memory card into your computer's card reader in order to be able to access the files on it, just as you would from (say) a USB memory stick.
If you've lost the adapter, you can buy one cheaply online
https://tinyurl.com/y48dyfql
or just ask your friends for one. (Since most mobile phones take microSD cards, there must be millions of people who've got those adapters stuck in drawers somewhere!).
If you computer hasn't got a card reader, you can buy a USB one online too. If you do so, you might as well buy one which accepts a microSD card
directly, cutting out the need for the card adapter altogether:
https://www.ebay.co.uk/itm/All-in-One-USB-2-0-Memory-Card-Reader-for-Micro-SD-SDHC-MMC-TF-M2-up-to-128GB/383802903855