I am tagging a box set of CDs made of 1970s vinyl recordings but I cannot find them anywhere but on Discogs.
Then it’s probably not entered yet. You should create the release on MB.
If it’s on Discogs, you can use the Discogs Import script GitHub - murdos/musicbrainz-userscripts: Collection of userscripts for MusicBrainz, by various authors (you have to install an extension like Greasemonkey – Get this Extension for 🦊 Firefox (en-US) to use this script)
But you have to do some correction, before you submit the new release, e.g. Discogs has different capitalization rules.
Great advice thanks. I have created a new release but I am worried about the capitalisation of no. op. and so on:
In English, op. and no. should not be capitalized → Style / Classical / Language / English - MusicBrainz
You could improve the Release by giving more information from your copy (go to the Edit tab):
Language: obviously English
Script: probably Latin
Barcode: in 1970 probably no barcode (checkbox)
Packaging: Cardboard/Paper Sleeve (if it’s not a gatefold cover)