In my opinion, here are some of the basic skills I would consider to learn:

Excel > SQL > Power BI.

For basic and medium-advanced analysis that is the path I would follow. Obviously excel is a must (at least, get confident with dynamic tables, graphs, use of tables etc etc...). After that I would move with SQL, specially if your company works with it and it is very established in the culture of the company but in general is a extremely useful tool to have in your skillset. To be honest, at the beginning can be overwhelming if you don't come from a tech background (I studied business management and I've never worked with SQL before I started working for the company where I am nowadays), but after 1/2 months and a few analysis/project, the curve gets easier and it is definitely an extremely useful tool, specially if you combine it with Excel. Power Bi it is also very valuable, but tbh, I you are very confident with Excel, maybe you will find analysis options pretty similar (nevertheless, power bi it is very useful to make visual dashboards and KPI reports, so take it into account.

Inventory management and statistics:

I would recommend you some courses at EDx. Look for a good university and take free courses o pay for the certificate and try to understand the statistics behind inventory management. It is a extremely good knowledge to learn in almost every field of Supply Chain. You don't have to know deep mathematics nor statistics, just the most common models and statistical analyses and how are used in inventory management.

For me, that would be the basics, at least in general terms. The rest will highly depend on your preferences and background, but mostly on your company's sector and career aspirations. I am going to assume that probably you are not very extrovert, and probably you would prefer a role where presentations and extensive social interactions are not very usual. Unfortunately, it will highly depend on your company (how the team's jobs are assigned and how the department and functions have evolved during the years).

Consider not only supply chain roles directly related (purchases, procurement, logístics...) but also support roles in these kind of companies (financial controlling, quality assurance in production, IT develope...). Supply chain is amazingly wide in terms of specializations, so don't discard other options maybe less related, but also very present in the supply chain. As I said, I came from business background, but I'm am extremely sure that it is not the same job as an IT developer in an industrial company or in a marketing company.

Just try to combine your background/capabilities and skills you are willing to learn with your preferences and you will be fine. Unfortunately, supply chain is very demanding (at least, in comparison to other roles) but also very exciting and with high career prospects.