Ok, thanks for clarifying. This is a much more manageable set of charges to work with. They seem pretty similar to one another so the process will be almost the same for creating all of these.
You will need to start on the shipping tab in the eCart object. From here you will add the first shipping charge rule:
Totalweight of cart <= 1kg the cost should be €6.50
You will give this charge rule a name, like up to 1kg, then you will add the first trigger. It will be set to 'subtotal for any column' then select the TotalWeight column and then you will select less than equal to (<=) and finally just enter the weight of 1.
For the calculation portion you will just add in a flat rate of 6.50.
The other rules will all be very similar except you will need to account for the lower weight with another trigger in the condition. For the second charge you would want to add a condition that says 'subtotal for any column, TotalWeight, >, 1'. This will ensure that the items that are less than 1kg are not charged for the 1kg and 2kg charges. So each rule afte the first one would also need to account for the column being greater than the last weight charge.
For the final part you will just need to add another charge based on the total weight being greater than 4kg, and if so you would multiply the total weight by 1 then minus 4.