https://link.to.blog.or.github.if.applicable
Talk about what makes you the best candidate for the job here, try and make it relevant to the job ad. Link out to blog posts, open source projects, case studies etc. if you're able to.
Go into detail of a few key skills here, again align to the job ad. Don't just list them, but list them with an explanation of what you did with the skill. e.g.
- Symfony - I recently developed a large CMS using Symfony, one feature of Symfony which really helped was the Workflow component which really helped us implement a robust system.
- Elasticsearch - I was involved in replacing a legacy search system with an Elasticsearch sysem that made use of it's aggregate feature to include a rich faceting feature.
Focus on the most recent position here, you can list a few others and if you have any particular achievements at those list those too, but you don't need to put everything.
If you have a relevant degree, mention that, plus any relevant certifications. You could mention A-levels and GCSE's but if you have other stuff you can talk about I wouldn't bother.
A short paragraph on what you like to do away from keyboard.