For variation 11 read Ševčík’s explanation of abbreviations markings, in particular about how the comma means to lift the bow.
For the first 7 bars the notes sometimes start from on the string, and sometimes from off the string (from the air). To help with having a gentle landing on the string, let the bow glide onto the string at the The place along the bow where the weight is evenly balanced. of the bow with flexible knuckles in the bow hand.
It can be useful to practice the rhythmic pattern of the 1st 7 bars on the open strings, firstly without the first finger on the bow and then with the first finger on for stability.
Think of how a plane lands with the rear wheels first and use some ‘active elbow stroke’ in the upper arm, that is as the down bow lands on the string the upper arm pivots up and as the up bow lifts off the string the upper arm pivots down.
Think about your Dividing the bowstroke into fractions of the length of the bow.. The dotted crochet takes you higher in the bow and the following quavers need to gradually regain the lost distance. Use the ‘zigzag bowing’ where you use more bow on the final up bow to get back to the balance point to start the new bar. You could use stickers on the bow to help understand the bow division that is needed here.
In bar 9, to lift the bow after the 5th note (which is a down bow), again use the upper arm to lift the bow off the string and settle it back into the string at the beginning of the bar.