What do I do with my savings?

I will probably be moving out soon and expect to need around €5-10k for furnishing the apartment, deposit etc. This would give me around €20,000 in my account, which is currently only there (Sparkasse). What would be the most sensible way for me to invest or use this money so that I would still have quick access to it if needed? The more detailed the better please, apart from capital-forming benefits & a few thousand euros in daily allowance, I've never had anything