Here's a good resource from the NHS. https://www.nhs.uk/start-for-life/baby/weaning/ Current recommendation is vegetables first. Just one 'meal' a day at the start- generally lunch is a good one but it can be whatever works for you. It won't take too long before you can include other meals and so fruit/ yogurt/ porridge etc but best to start with just a little as they aren't used to it and have tiny tummies.
Solid starts is also a good app for advice on how to cut eat food Don’t pay just the free one is fine x
We start with just one meal per day. The lunch:)