It will depend on your plan @Virgaudas but it looks like the product consumes 6 to 6.5kw per hour so if you multiply this by your price per kWh that will be the cost. 
Most of these appliances are not on full for the whole time as they switch when getting to temperature so the calculation is not accurate but it will give you an idea

That sheet doesn't show the power of each ring on the hob so I've done some digging around. I think it has two different sizes of heating elements. Is that correct?

The larger element is 1800w while the smaller is 1200w. If the large element is on full for an hour it will use 1.8kWh (about 63p). The small element on full for an hour will use 1.2kWh (about 42p).

That is if it's on full but you're unlikely to do that. At the risk of stating the obvious, you'd have it on full to heat a pan then turn it to a lower setting, which will use less electricity, to simmer.

I hope that's helpful.

I have what I think may be ‘radiant’ rings. The small one uses about 0.6kW when I switch it on with a 1kg pan on it, the larger one 1.2kW. This means the little one would use at most 0.6kWh if was on continuously for an hour, the big one 1.2kWh. The actual use would be much less, though, because they switch off when they think the pan is hot enough. If your electricity costs, say, 46p/kWh on average (like mine does), the little ring would cost at most 23p per hour, the big one 55p. The actual cost would probably be only a fraction of these figures.

That hob uses more powerful elements. It isn't shown in the specification but the parts are shown on this website.

https://www.partmaster.co.uk/cooker-oven/cchobkn13-0065306900628235/element/catalogue.pl?shop=currysessentials&path=560818&model_ref=2598344&refine=element

So basically it is impossible to calculate even approximate cost of electricity because heaters switch off intermittently (which obviously I am not tracking when they switch on and when they switch off)? Of course I am not interested at price if it is on full because as you guys mention, actual cost might be at least 2x lower.. Plus different heating programmes (that are from 1 to 6) could reduce cost even more. I don't even know know anymore why I even asked such question.. does anyone know how to solve that? If not, no problems, just curious to give last chance to solve this matter 

Please ignore this because I can't delete post.

Is there some kind of general information to decide electricity cost of various appliances like washing machines that have all kinds of programmes as well that complicates problem? Am I thinking correctly that I should look for "power consumption" in kWh and just like @BPLightlog mentioned? I guess without smart meter, it is impossible to know?

Perhaps this might help 

https://www.nea.org.uk/wp-content/uploads/2022/03/Electricity-Consumption-Around-the-Home.pdf

As you mention, the actual cost will vary depending on actual use and your own price per kWh that you pay

You could also compare appliances by looking at the energy rating shown. These give letter categories A or A+++ being best (lower cost to run)