a database appears similar to a spreadsheet, because both present data via a "datasheet" format.
however most excel users manage their spreadsheets without needing any vba code (just simple formulas) and without needing to "structure" the data.
to use a database, the data needs to be split into a series of related tables (akin to datasheet tabs in a spreadsheet). each table consists of a set of fields (columns in a spreadsheet).
eg - lets say one sheet has customer details. another will have order details. the order details sheet will include a reference of some sort to identify the customer. The relevant customer details can be obtained from the referenced row on the customers sheet
so a significant difference is that in a database, you will need to structure your data into a series of related tables, generally with many more tables (datasheets) than you would ever have in a spreadsheet. each column of a database table should comprise data of a particular type only, which maintains the integrity of a data.
with a database all the tables are interrelated. you can select a subset of data from one table, and expand this by selecting related data from other tables - and sort and structure the output to provide exactrly what you want.
in order to do all this, with a database - you need additional skills over and above those needed to design a spreadsheet. you need to understand data analysis, and you will need to be able to use vba.
one important feature of a spreadsheet that you need to try and forget is the ability to base a caclulation on a different row of the spreadsheet. databases work on considering "sets" of data, with no particular order. effectively you throw all your data into a bucket,. to use the data you take out all the data that meets a certain set of criteria. the order doesn't matter - just the totals.
you CAN process the data in a particular order, but it really is better to try and avoid this.
because of all this, complex databases are far harder to create than complex spreadsheets, and would be virtually impossible to do without a decent foundation of skills as a starting point. hence the suggestion others have made that the best way is to start learn with something much more basic.
access is so very difficult to understand and use, that a lot of stuff we do in access is explicitly designed to limit and control what users can do with the data to prevent accidental and catastrophic damage to data. it isn't like any other application, where you can "save" or "discard" edits if you change your mind. Changing database data is immediate and non-reversible.
this isn't meant to imply that access is well, not accessible - it is, but to get the most out of it, it needs to built on a very solid foundation. And as far as transferrable skills go, once you get used to using databases, you might find it hard to go back to spreadsheets in a lot of cases.
good luck