Our recently acquired Honda Stepwagon conversion doesn't have any sort of rail into which an awning could be attached (which is how it works if I understand other people's photos online).
Is fitting one straightforward ? Presumably I source one and drill holes into the body or use self-tapping screws?
Are rails / awnings standard lengths and should I go for a C-shape or Figure of 8 ?
Alternatively, I've seen some type of setup on some people's vehicles which presumably are a type of awning-in-a-box. Is this solution recommended instead?
You can get a 'Magnetic Awning Rail' that fits to van roof (assuming roof panel is steel, and that should not be taken for granted with modern vehicles! - check with a magnet before purchasing rail!) in a temporary 'as and when needed' fashion, so no drilling of holes required.
Heard people not owning/using one casting doubt on it's ability to stay in place, but never seen anyone with one post about finding fault! - make of that what you will.
I'd be cautious of drilling holes for rail fixing (not saying don't, just check first!) - check there is no wiring in the void behind where you would be drilling AND that screw points can't chaff wiring after fitting! - damaged wiring is expensive to replace/a pain to fix and can cause fires! Also every hole is a potential water leak point! - probably the vast majority of water ingress in caravans occurs on the awning rail fixings! - you need the correct time/weather durable sealant to avoid leaks.
If you've a reasonably flat surface to attach to, a roll of double-sided adhesive strip can be used to attach an awning rail. We used this method on our previous VW camper (as advised by a dealer) and it held securely for several years.
Your Honda is recently acquired, you say. Don’t necessarily assume you need an awning! we have a wind out one & never use it. I’d suggest you enjoy your camping this year & see if / when you miss an awning - and what its function will be. A drive away awning takes up weight allowance & space, both of which are limited in a MH.