Welcome @Randomchat . The UCAS website is pretty good at explaining the process, including for entrants not at school.
A few more dates added below. As always, if you are aware of anything not there, please copy and paste the list and add it in.
Open Days
Mon 22 June - Edinburgh
Weds 1 July - Dundee - Medicine
Tues 25 August - Aberdeen
Tues 1 September - Strathclyde
Weds 2 September - Glasgow, Robert Gordon/Gray's
Fri 4 September - GCU
Sat 19 September - Stirling
Sat 26 September - Abertay, Dundee, Edinburgh, Heriot-Watt (Edi), Napier, QMU, UWS (Lanarkshire)
Sat 3 October - Aberdeen, GCU, Glasgow (Dumfries), Strathclyde
Weds 7 October - UWS (Ayr)
Thurs 8 October - UWS (Dumfries)
Fri 9 October - Heriot-Watt (Galashiels)
Sat 10 October - St Andrews
Sat 17 October - UWS (Paisley)
Sat 24 October - Abertay, Edinburgh, Glasgow, Napier, Stirling
Weds 28 October - St Andrews
Fri 30 October - Heriot-Watt (Galashiels)
Sat 31 October - Dundee, Robert Gordon/Gray's
Sat 7 November - Heriot-Watt (Edi), QMU
Sat 28 November - Robert Gordon/Gray's
Wed 14 April 2027 - St Andrews
SRUC - various dates for different courses and campuses
GSA - various online sessions & tour dates
RCS - open days have passed, online events available
UHI - various dates for different courses and campuses
UCAS Discovery Dates
Thurs 27 August - Stirling (university)
Weds 2 September - Dundee (university)
Thurs 3 September - Carnegie Conference Centre
Tues 8 September - Robert Gordon
Weds 9 September - UHI Elgin
Thurs 10 September - UHI Inverness
Tues 15 September - Glasgow SEC
Weds 16 September - UWS Lanarkshire
Thurs 17 September - Ayrshire College, Kilmarnock
Tues 22 September - Edinburgh Royal Highland Centre
Tues 29 September - Easterbrook Hall Dumfries
UCAS Dates
2026
28 April - Courses show in UCAS search tool
12 May - Registration opens and applications open for drafting
9 July - Conservatoire applications open
[4 August - QS H/AH results]
1 September - Completed applications can be submitted (with reference)
15 September - Equal consideration date for Oxbridge, and most courses in medicine, dentistry, and veterinary
1 October - Conservatoire music courses application deadline
15 December - Application deadline for PGCE courses in Wales
13 January - Equal consideration date for most undergraduate courses
13 January - Conservatoire deadline for most undergraduate dance, drama or musical theatre courses
25 February - Extra opens (if used all five choices and not holding any offers)
30 June - Applications received by this deadline will be sent to universities and colleges. After this time, applications are automatically entered into clearing
1 July - Last day to add an Extra choice
2 July - Clearing opens
23 September - Final date for 2027 entry applications
23 September - Conservatoire final date for applications
18 October - Last date to add a clearing choice